Stop 4: Cross-stratified Sand

Sandstone with layers at different angles.
Cross-stratification of sandstone can be seen near the concrete stairs on the Saddle Rock Trail.

NPS/Eric Grunwald

Quick Facts
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Scenic View/Photo Spot

At the set of stairs, look at the cliff face to the left of the trail. The very fine to fine-grained sandstone along this cliff face is cross-stratified or cross-bedded, meaning some of the layering of sediments is at an angle to the main bedding plane.

Cross-bedding suggests that the sandstone here was deposited in an environment where a flowing medium was involved, usually water or wind. Geologists interpret the structures here as products of wind-ripple migration on aeolian dunes. 

To continue with the tour, continue down the trail about 75 feet from the concrete stairs. Here we have seen how wind and flowing water can change rock. Do you think living things can affect geologic processes? 

Scotts Bluff National Monument

Last updated: December 15, 2020